const LEVEL_4 = {
    id: 4,
    name: "第4关-双子Boss",
    maxRounds: 10,
    target: [
        { type: "monsters", count: 20, description: "怪物: 0/20" },
        { type: "boss", count: 2, description: "击败Boss: 0/2" }
    ],
    bossHealth: 10, // 调低Boss血量，使策略执行更可行

    // 优化初始布局，确保有更明确的连接路径
    initialBoard: [
        [1,  2,  6,  3,  6,  2,  1 ],
        [2,  8,  2,  2,  2,  3,  3 ], // 左侧Boss，周围放置相同类型怪物
        [6,  2,  2,  3,  3,  3,  6 ],
        [3,  1,  2,  9,  2,  1,  3 ], // 主角在中心
        [6,  1,  1,  3,  1,  1,  6 ], // 增加相同怪物成群的区域
        [3,  3,  1,  1,  1,  8,  2 ], // 右侧Boss，周围放置相同类型怪物
        [1,  2,  6,  3,  6,  2,  1 ]
    ],


    pathGuarantee: true,
    
    // 保证特定位置总是有战略性元素
    strategicPositions: [
        { row: 2, col: 3, types: ["monster", "gem"] }, // 靠近中心的关键位置
        { row: 4, col: 3, types: ["monster", "gem"] }
    ],

    // 调整掉落概率，增加策略性元素出现频率
    roundRanges: [
        {
            startRound: 0,
            endRound: 4,
            dropRate: {
                monster_blue: 30,
                monster_pink: 30,
                monster_red: 25,
                gem: 15 // 增加宝石掉落率
            }
        },
        {
            startRound: 5,
            endRound: 7,
            dropRate: {
                monster_blue: 25,
                monster_pink: 25,
                monster_red: 25,
                gem: 15,
                wood: 10 // 增加木材掉落率
            }
        },
        {
            startRound: 8,
            endRound: 10,
            dropRate: {
                monster_blue: 25,
                monster_pink: 25,
                monster_red: 20,
                gem: 20, // 后期大幅增加宝石掉落率
                wood: 10
            }
        }
    ],

    defaultDropRate: {
        monster_blue: 30,
        monster_pink: 30,
        monster_red: 30,
        gem: 10
    },
    
    // 连击奖励机制：当一回合内消除多个怪物时提供额外奖励
    comboRewards: {
        threshold: 5, // 连击5个以上时触发
        extraGem: true, // 下一回合额外掉落宝石
        sameTypeBonus: true // 确保下一回合有更多相同类型怪物
    }
};
